Greener synthesis of functionalized-GO incorporated TFN NF membrane for potential recovery of saline water from salt/dye mixed solution

Abstract

Membrane is often aimed to achieve high rejection rates against salts and dyes in order to produce high quality permeate. However, large amount of salts presents in textile wastewater could be recovered and reused for dyeing process. In this work, we fabricated new thin film nanocomposite (TFN) membrane with improved surface properties using emerging mist-based interfacial polymerization technique in an attempt to recover salts from salt/dye solution. Prior to membrane fabrication, graphene oxide (GO) was surface-functionalized using greener approach to improve its dispersion in solution for better distribution within membrane selective layer. Compared to control GO, acrylic acid (AA)-modified GO was able to improve pure water permeability (PWP) of TFN membrane by 6.6%, reaching 11.34 L/m2·h·bar. Its PWP was also higher compared to thin film composite membrane (~25% enhancement) owing to enhanced membrane hydrophilicity coupled with formation of thin yet highly crosslinked PA upon modified GO incorporation. When tested using salt/dye mixture, the best TFN membrane could recover 79–86% of NaCl from the feed, producing saline permeate containing <0.3% pigment. The high NaCl recovery achieved by the TFN membrane coupled with excellent dye rejection offers a solution for potential reuse of saline permeate for dyeing process.